Two free software converters

Stanza will convert all kinds of text into several ebook formats, including the proprietary .azw format Amazon uses for its own Kindle texts. You can also use Stanza to read texts directly on the screen in a clutter-free layout. Apple and Windows.

Mobipocket Creator will produce .prc files that can be displayed on your Kindle. Windows only.

You can also use Mobipocket Desktop to manage your ebooks and RSS feeks, then sync them to your Kindle whenever you connect it via USB. However, you have to use version 6.0, not any of the later versions (such as 6.1 or 6.2).  Amazon, which owns Mobipocket, has removed support for the Kindle from more recent versions. (Shame on you, Amazon!)

Pros: Easy to use, free, fast, works consistently

Cons: Windows only, RSS feed management is limited; for Desktop manager, most recent versions lack Kindle support.

An alternative RSS solution:

From the blog interface.puhala.com comes this helpful advice on how to cheaply create your own customized newspapers and blogs. You’ll need the following services and items:

• A free account at FeedJournal: http://feedjournal.com
• Some RSS feeds you’d like to subscribe to
• The free “full rss feed” tool on this website:  http://labs.echoditto.com/fulltextrss

Pros: Free!

Cons: Lots of fine-tuning required, FeedJournal is not very easy to use and tends to produce errors frequently. Can be very slow at times.